International truck maker Navistar and self-driving truck company TuSimple have announced plans to begin producing autonomous trucks by 2024 alongside the roll out of TuSimple's United States autonomous freight network. The partnership will see the companies move away from retrofitting the Navistar International commercial trucks that TuSimple currently uses, in favour of developing trucks designed specifically for autonomous driving. TuSimple currently operates a fleet of 40 self-driving trucks in the United States used for testing purposes and to carry freight between Arizona and Texas. TuSimple's trucks operate at Level 4 autonomy, which means they can navigate a range of environments, weather and safety conditions without driver assistance. However, legal requirements in most states require a driver to be present at all times. TuSimple plans to demonstrate fully driverless operations in 2021.